We are all familiar with the little putting cups golfers use in order to practice their putting skills in the office or at home, when there is not enough time or the weather is too bad to get out on the golf course. These putting cups simply rest on the floor and include a substantial incline to get the ball up high enough so it can then fall into the cup.
Of course, the substantial incline is not very representative of a typical putting situation on a golf course, in which the ground leading up to the hole is relatively level or slightly inclined. Therefore, the practice the golfer gets putting into a putting cup in the office is probably not very useful as a preparation for putting on the golf course.
Also, the known putting cups are in the way when the golfer is not golfing and have to be stored away when not in use. This requires the golfer to take the time to set them up and put them away for each use or else risk somebody tripping over them.